Free Practice Questions for Juniper JN0-460 Exam

AMarvis Actions Missing VLANnotification indicates that anaccess pointis missing a VLAN configured on other APs within the same site.

Marvis identifies configuration inconsistencies by comparing VLAN assignments across devices.

Juniper Mist automatically classifies ports to simplify visibility and automation withinWired Assurance. The Mist cloud analyzesport telemetryandlink behaviorto determine port roles, including uplinks.

“Mist uses machine learning and switch telemetry to automatically detect uplinks by analyzing traffic behavior and topology information. Uplink ports typically exhibit higher TX/RX utilization and are identified as spanning-tree root or forwarding ports connecting upstream devices.”

Option A:Correct — Mist examines traffic statistics. Ports with significantly higher TX/RX utilization relative to others are likely uplinks.

Option B:Incorrect — MTU size is not a classification criterion.

Option C:Correct — Mist usesSTP information(root or designated port status) to identify uplinks.

Option D:Incorrect — port description fields are for administrative purposes only and are not used by Mist analytics.

According to Juniper Mist documentation, the term "Adopting a Switch" specifically refers to the process of bringing an existing, already-configured switch—often termed a brownfield device—under the management of the Juniper Mist cloud. This is distinct from the "claiming" process, which is reserved for greenfield environments where new, factory-default switches are added using a QR code or activation code.

In a brownfield scenario, the switch is typically already in production or has a pre-existing local configuration that must be preserved or integrated into the Mist AI-driven dashboard. To adopt such a switch, the administrator must manually interact with the switch's Command Line Interface (CLI). The Mist portal provides a unique adoption command—a string of Junos OS configuration—that includes the specific URL for the Mist cloud and the organization’s unique registration token. Once this command is pasted into the switch's CLI and committed, the switch initiates an outbound connection to the Mist cloud via TCP port 2200 or 443.

Upon successful connection, the switch's status changes from "Unassigned" to "Connected" in the Mist dashboard. This transition allows the Mist AI engine to begin collecting telemetry, monitoring Service Level Expectations (SLEs), and performing automated troubleshooting. While the adoption process allows for "monitoring only" mode to avoid disrupting existing services, it is the fundamental first step for transitioning legacy Juniper infrastructure into a modern, cloud-managed Wired Assurance environment. This workflow is essential for organizations looking to leverage Marvis AI and automated operations without having to factory-reset their entire existing network.

According to Juniper Networks technical documentation regarding "Bridging and VLANs," Layer 2 network segmentation is primarily achieved through the implementation of Virtual Local Area Networks (VLANs). While VLANs provide critical segmentation services by grouping related devices into independent logical networks and containing broadcasts within specific domains, they are bound by the architectural constraints of the IEEE 802.1Q standard.

A fundamental limitation of this traditional Layer 2 approach is the address space of the VLAN identifier. The 802.1Q header allocates exactly 12 bits for the VLAN ID (VID). This mathematical constraint limits the total number of possible VLANs to 4,096 ($2^{12}$). Within the Junos operating system, VLAN IDs 0 and 4,095 are strictly reserved for system internal functions and cannot be assigned to user traffic, resulting in a maximum of 4,094 usable VLANs for network segmentation.

In modern enterprise environments—especially those involving large-scale multitenancy, cloud services, or high-density campus deployments—this 4,094 limit often becomes a significant bottleneck. Network administrators can exhaust this pool when attempting to provide granular isolation for thousands of unique device types, departments, and guest users. To overcome this specific limitation, Juniper recommends moving toward EVPN-VXLAN campus fabrics. VXLAN technology replaces the 12-bit VLAN tag with a 24-bit VXLAN Network Identifier (VNI), which theoretically supports over 16 million unique segments. This vast increase in scalability allows for the creation of administrative domains that far exceed the capabilities of traditional Layer 2 Ethernet bridging. While Layer 2 domains also face challenges related to Spanning Tree Protocol (STP) complexity and large broadcast diameters, the numeric exhaustion of the VLAN ID space remains the most definitive hardware-level limitation of standard Layer 2 segmentation.

According to Juniper Mist documentation, the Throughput Service Level Expectation (SLE) is the primary metric used to represent the ability of wired users to pass traffic across the network without impedance. This SLE provides a comprehensive oversight of network performance by identifying issues that degrade the user experience, such as storm control events, interface anomalies, and specifically uplink congestion.

Within the Throughput SLE, the Congestion classifier (also referred to as Congestion Uplink) is specifically designed to monitor for buffer saturation and packet drops (TxDrops). When traffic arriving at an interface exceeds its processing or forwarding capacity, packets are queued in a buffer; if this buffer becomes full, the switch begins dropping packets. Juniper Mist utilizes a specific formula considering the ratios of TxDrops to TxPackets, Transmitted bps to Link Speed, and Received Speed to Link Speed to determine if a "Bad User Minute" has occurred due to congestion.

A critical feature of Wired Assurance is the automatic identification of uplink interfaces. Mist identifies these high-capacity ports by analyzing switch telemetry for characteristics such as having a switch or router as an LLDP neighbor, being designated as a Spanning Tree Protocol (STP) root port, or exhibiting significantly higher packet counts compared to access ports. When congestion is detected on an interface identified as an uplink, the system recognizes that this bottleneck impacts every user on that switch. By correlating these drops with the Throughput SLE, network administrators can proactively identify when a site requires more bandwidth or a different fabric architecture to handle current traffic demands, rather than simply monitoring if the link is physically "up" or "down".

According to Juniper Mist documentation regarding campus fabric design, the campus fabric IP Clos (also known as a 5-stage Clos) is the architecture that extends the EVPN-VXLAN protocol stack from the core tier down through the distribution tier and finally to the access tier. In this model, every switch in the hierarchy—from the high-capacity core switches to the wiring closet access switches—participates in the EVPN control plane and VXLAN data plane.

By extending EVPN-VXLAN to the access tier, the IP Clos architecture provides a standards-based, scalable framework that allows for seamless Layer 2 connectivity over a Layer 3 underlay across the entire campus333333333. This enables advanced features like Microsegmentation using Group-Based Policies (GBP) and Macrosegmentation via Virtual Routing and Forwarding (VRF) instances directly at the edge of the network.

In contrast, other architectures like "core-distribution" (either CRB or ERB) typically limit the EVPN-VXLAN fabric to the core and distribution layers, leaving the access tier to connect via traditional methods like LAG, Virtual Chassis, or standard Layer 2 trunks5555. The IP Clos architecture is specifically designed for large-scale deployments where high density, vendor interoperability, and end-to-end policy enforcement are critical6. By utilizing a 5-stage IP Clos, organizations can eliminate the complexities of Spanning Tree Protocol (STP) while maintaining a flexible, "any-to-any" communication path throughout the physical infrastructure.

WhenMarvis Actionsdisplay “AI Validated,” it indicates the issue was detected earlier but is nowresolved.

Marvis automatically validates remediation and marks the action closed once the anomaly clears.

According to Juniper Networks' EVPN documentation, an EVPN Type 4 route, also known as an Ethernet Segment route, is a critical component of the BGP EVPN control plane used specifically in multihoming scenarios. When a Customer Edge (CE) device is connected to two or more Provider Edge (PE) routers via a Link Aggregation Group (LAG), these PE routers must coordinate to manage traffic flow and prevent network loops.

The primary purpose of the Type 4 route is to enable Designated Forwarder (DF) election. In a multihomed Ethernet Segment (identified by a unique Ethernet Segment Identifier or ESI), only one PE router—the Designated Forwarder—is permitted to forward Broadcast, Unknown unicast, and Multicast (BUM) traffic from the EVPN core to the CE device. Without this election process, multiple PE routers would forward the same BUM packets to the CE, leading to traffic duplication and potential broadcast storms.

The workflow begins when a PE router is configured with an ESI on a physical or logical interface; it then generates and advertises a Type 4 route to all other PE routers in the network. This route carries the ESI and an "ES-import" extended community, which allows other PEs connected to the same segment to automatically discover their peers. Once these "peering" PEs are discovered, they collectively execute a DF election algorithm—such as the default modulo-based algorithm or the newer preference-based algorithm—to select the DF and Backup Forwarder (BDF) for each VLAN or bridge domain. By ensuring a deterministic and synchronized selection of the forwarder, Type 4 routes provide the foundational stability required for active-active and active-standby multihoming in modern campus and data center fabrics.

According to Juniper Mist documentation, Dynamic Port Configuration (DPC)—also referred to as Dynamic Port Profiles—is the feature specifically designed to automate the assignment of VLANs and port settings based on the type of device connected to a switch. This technology enables the concept of "colorless ports," where any device (such as a Juniper Mist Access Point, an IP camera, or a VoIP phone) can be plugged into any available switch port without prior manual configuration.

The system functions by using "port assignment rules" that leverage various device properties to identify the connected hardware. These properties include LLDP attributes (System Name, Chassis ID, or Description), MAC addresses (including specific OUI ranges), and RADIUS attributes. For example, a rule can be configured to detect an LLDP System Description starting with "Mist Systems" and automatically apply a "Wireless AP" port profile. This profile typically includes the management VLAN, PoE settings, and Spanning Tree Protocol (STP) parameters required for an access point to function.

The primary benefit of DPC is the reduction of manual labor and the elimination of configuration errors in large-scale deployments. In traditional environments, an administrator would have to manually assign a VLAN to a specific physical port; with DPC, the Juniper Mist cloud detects the device and pushes the relevant configuration to the switch in real-time. If the device is disconnected, the port can be configured to revert to a "restricted" or "guest" VLAN, ensuring that the network remains secure against unauthorized access. This AI-driven approach drives consistency across multiple sites while significantly streamlining the onboarding of new hardware.